{"id":"CVE-2026-98682","title":"smb: client: drain and invalidate before server-side copy/clone","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: drain and invalidate before server-side copy/clone\n\ncifs_file_copychunk_range() and the clone (FICLONE) path of\ncifs_remap_file_range() do not serialise th…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= c54fc3a4f375663f2361a9cbb2955fb4ef912879 < dc71660f11ef2fecc0695a41e49cd496a9d255ab","Linux >= c54fc3a4f375663f2361a9cbb2955fb4ef912879 < c9b1194e8ec99d95db25db45edd2fbf690f043ab","Linux 358bd5f436d820bb758833050aae065b35d6986c","Linux 43801359c8971cc49b4a4db5015fba77fbd09c32","Linux >= 6.1.68 < 6.2","Linux >= 6.6.7 < 6.7","Linux 6.7"],"published":"2026-10-18","updated":"2026-10-19","sourceUpdated":"2026-10-19T09:23:52.548Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98682","references":[{"url":"https://git.kernel.org/stable/c/dc71660f11ef2fecc0695a41e49cd496a9d255ab"},{"url":"https://git.kernel.org/stable/c/c9b1194e8ec99d95db25db45edd2fbf690f043ab"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.529Z","slug":"CVE-2026-98682","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: drain and invalidate before server-side copy/clone\n\ncifs_file_copychunk_range() and the clone (FICLONE) path of\ncifs_remap_file_range() do not serialise the destination page cache\nagainst the server-side copy the way the other server-side range\noperations (smb3_zero_range(), smb3_punch_hole(), smb3_collapse_range()\nand smb3_insert_range()) do.\n\ncifs_file_copychunk_range() invalidates the destination range with\nfilemap_invalidate_inode(), which takes and drops the mapping's\ninvalidate_lock internally, so the lock is no longer held when the\ncopychunk ioctl is issued.  It also never drains in-flight netfs I/O on\nthe target.  The clone path never takes the invalidate_lock at all (only\ni_rwsem), uses a bare truncate_inode_pages_range() and likewise does not\ndrain outstanding I/O.\n\nAs a result an asynchronous destination writeback can complete after the\nserver-side copy/clone has run and reinstate stale data over the region\njust written by the server, corrupting the file.  This is the same class\nof corruption as commit d7d2adcd022b (\"smb/client: flush dirty data\nbefore punching a hole\") and has been seen randomly in generic/363\nagainst Windows Server.\n\nFix both paths to follow the established ordering: hold the target\nmapping's invalidate_lock across the flush and invalidation of the\ndestination and the server ioctl, and call netfs_wait_for_outstanding_io()\non the target to drain in-flight writes before the ioctl is issued.  Only\nthe target inode's invalidate_lock is required, as the source is merely\nflushed and not invalidated; i_rwsem (already held via\nlock_two_nondirectories()) is acquired before the invalidate_lock,\nmatching the VFS lock ordering.  Since filemap_invalidate_inode() takes\nthat same lock internally, replace it with its own unmap/flush/invalidate\nsteps instead of calling it, and return early on a zero-length copy to\navoid a range underflow.\n\n## Affected\n\n- `Linux >= c54fc3a4f375663f2361a9cbb2955fb4ef912879 < dc71660f11ef2fecc0695a41e49cd496a9d255ab`\n- `Linux >= c54fc3a4f375663f2361a9cbb2955fb4ef912879 < c9b1194e8ec99d95db25db45edd2fbf690f043ab`\n- `Linux 358bd5f436d820bb758833050aae065b35d6986c`\n- `Linux 43801359c8971cc49b4a4db5015fba77fbd09c32`\n- `Linux >= 6.1.68 < 6.2`\n- `Linux >= 6.6.7 < 6.7`\n- `Linux 6.7`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}